Furnace roof



C. G. POTH FURNACE ROOF March 2, 1954 Filed Jan. 26, 1951 2 Sheets-Sheet2 Patented Mar. 2, 1954 2,670,693 FUEQNACE 15001 Ciereliee Ge Beth,.East Canton, Ohio,

' te Republic Steel Gerreretieri,

e.. corporation f New J ereey v assignor Cleveland, Ohio? ApplicationJanuar-y 26, 19571, Serial No. 208,010

0 Claims,

invention relates generally to wall con? struction iormetallurgicalfurnaces and is Dar,- ticularly concerned with a brick work-constructionwhich is suitable for the ywalls of such turnaces which are subjected tothe most severe serve ice conditions, such as the roof and knuckle wallsof an open hearth furnace and electric furnace roofs.

Many efforts have been made heretofore to improve the roof constructionof metallurgical furnaces, such as open hearth and electric furnacesused in the steel industry, but there is still much to be desired in themost highly de Veleped .reef eeiietriieteiie 0f the present day. Suchroofs have a short life at best before patchinc ie required en@ repeatedsete-,hiee must be debe frequently te lieee the furnace irl operation.Muehleriger reef life ie desirable beeauee ef the expense required forpatching or replacing the patched roof, this expense including the,iossof Dreduetieii .dering the time the ierneee isv being so repaired.

There ere comparatively few materiele which are at all suitable for useas roof construction material in open hearth furnaces and the like.Chief among these materials are silica brick and betie briekf Sila blcare Well Suited t9 $119? 11S@ il? d numbr 0f JFSSDGS.- They are SOQgzbigii? t9 melt et e temperature ef approximately 3,999" F, and areresistant to erosionby gases. ever, the heet eenduetivity ef eilieebritte. ie considered only fair.

Basic bricks are. suitable for such use some reeeeete but Het in etherrespeete Ae eeieeered with silica brick they are much heavier but theyare weaker, more resistant to erosion and begin te melt et highertemperatures. Besie brieke ere so *heavyv that a large open hearth roofconstruct? ed of them must 'be supported by suspending meene- PFOPOSSShave been mage t0* 11s,@ 91.115 mear CQYQrSd bsf? brick ill ftlmae, .YQQv3,01-5'01i1(5.?095 but such proposals have net Solved the. emblembecause YQH Xd which Was ,fmd Q11 Q Dicke@ 117D by the double thekneeeei metal between tbe rows' of bricks resulted in growth of the bricksand resultant buckling andfspalling rof the roof.

The present invention is predicated on the dis.- covery that new andunexpected results may be obtained by utilizing in furnaces of the typehere under consideration e Well eeiietriietien eemf Dl'vsllg rOWS 0iSmc@ bc 0n QQQQSQ Si Pf erle er tw@ .reve et betie britt eeeh ef thebetie brieke, preferably but not necessarily, heise,

It has been found in cased in a metal shell.

actual practice that when furnaces have such a construction in the partsofthe roof and knuckles heats as the best conventional furnace betweenVsuccessive patchings As illustrative of these new and surprising result,it may be said that open hearth furnaces embodying the present inventionhave been operated to produce 50% more heats before the rst patchingthan was possible with the best conventional prior art roofconstruction.

The new and surprising results attained by the present invention arebelieved to be traceable to the new combination of parts and the newresulting mode of operation. The combination of silica and basic brickprotects the construction against erosion, oxides and resultantspalling. This in turn strengthens the construction by bonding thebricks together. It enables the more highly conductive basic brick toconduct heat away from the silica brick and thereby keep the temperatureof the latter at a lower level. The arrangement of the rows of silicaand basic bricks prevents any material lateral growth and leepeblieb-.ling ef the reef et the minimum Ae a result the roof is lightenough and strong eheheh eed there eed .site maintaining te be'self-supporting and not to require overhead supports, Moreover, thesurfaces of the basic briikrwhch im? 53.229058@ t0 the gases rapidly pk.iiD .CITQQS oxide from the gases afld thus the Slizlfes Y the .innerSer-feces ef ,the silice brieke.- ,This iti- Were eiteiisiee ef thebeeie briek etree e Sert of washboard eect to the furnace wall andaffords protection to the silica brick against the erosive effects ofthe gas since the rapid ilo-w of the gases is interfered with and thegases are agitated and are deflected away from the silica brick by therib-like projection of the basic bricks.

The present invention will be better understood by those skilled in theart from the drawings which accompany and form a part of this speci#fication and in which:

Fig. l is an elevational view partly in section taken longitudinally ofan open hearth furnace embdyng the present invention;

Fia i is a transverse, Sectional View et the:

furnace of Fig. 1;

ei .there brick grew inwardly revendY Fig. 3 is a perspective-like viewof a part of the roof of Fig. 1 on an enlarged scale;

Fig. 4 -is a perspective-like view of a furnace roof embodying thepresent invention after having been in use for some time;

Fig. is a fragmentary, bottom, plan view of an electric furnace roofembodying the present invention; and

Figure 6 is a perspective view of one of the metal encased basic bricks.

In Figs. l, 2 and 3, the back wall of an open hearth furnace isindicated at i and part of the roof is indicated Iat 2. This roofincludes rows 3 of basic brick encased in metal 3a and rows 4 of silicabricks. The rows 3 of metal covered bricks are preferably arranged inpairs, each pair extending varying distances from the back wall l sothat the ends of adjacent rows in the roof do not lie on the same linelongitudinally of the furnace. One or more rows of silica bricks may beinterposed between two pairs of rows of the metal covered basic bricks.If desired, the basic bricks may be laid in single rows and one or morerows of silica brick may be laid between adjacent single rows of thebasic bricks.

It has been found that it is unnecessary to extend the rows of metalcovered basic bricks all the way across the roof of the furnace and whenthese rows extend upwardly along the roof approximately as is shown inFigs. l and 3, excellent results, in terms of the number of heats thatcan be made in a furnace before patching is required, may be expected.

Fig. 4 shows, fragmentarily, the appearance of the inner surface of theopen hearth-furnace roof embodying the present invention after longcontinued use thereof. In this figure, 3 indicates rows of basic brickwhich were covered with metal, and 4 indicates silica brick, both asshown in Figs. l to 3. It will be noted that the lower or inner surfacesof the metal covered bricks have material 6 adhering thereto whichprojects downwardly well beyond the inner surfaces of the silica bricks.This material includes iron oxides which were carried by the gases andwere deposited on the metal covering 3a of the basic bricks. Thisadhering material gives the inner surface of the roof a washboard effectas can be seen in Fig. 4, the effect of which configuration is thatgases flowing along the roof are agitated and deflected away from thesilica brick and the eroding effect of the gases is surprisinglydecreased with resultant prolonged life of the silica bricks.

Fig. 5 shows the lower side of an electric furnace roof in which thebasic brick 3 are arranged in rows extending along generally radiallines in the roof with the silica brick i completing the roof. While thearrangement of bricks in this roof is not exactly like that in the openhearth furnace roof of Figs. l to 4, this operation and results aresubstantially the same.

It has also been discovered, as a result of tests of this invention inroofs of metallurgical furnaces operating over long periods of time,that the basic bricks become fused to the silica brick during use and,hence, have a fairly good heat conducting connection thereto. The use ofmetal cases on the basic bricks improves the heat conducting contactwith the adjacent silica bricks and thus act as good conductors to carryheat from the silica bricks into the basic bricks whence it may becarried away more rapidly than through'A the silica bricks themselveswith resulta-nt maintenance of the roof at a lower temperature thanwould otherwise be the case.

In the appended claims the expression complete solid wall or roof wallrefers to the brick portion of the wall or roof and is not intended toexclude openings such as the electrode holes in the roof of the electricfurnace of Figure 5.

Having thus described the present invention so that others skilled inthe art may be able to understand and practice the same, I state thatwhat I desire to secure by Letters Patent is defined in what is claimed.

vWhat is claimed is:

1. A complete solid wall for a metallurgical furnace comprising aplurality of rows of silica bricks and a plurality of composite rows ofbricks arranged alternately with said rows of silica bricks, each ofsaid composite rows consisting of basic bricks disposed in juxtaposedrelationship with each other thereby constituting a continuous part ofsaid row and silica bricks constituting the remainder of said row, thenumbers of basic bricks being diierent in adjacent composite rows withthe basic bricks at one end of the basic brick parts of said rows beingpositioned in staggered relation relative to each other.

2. A complete solid wall for a metallurgical furnace comprising aplurality of rows of silica bricks and a plurality of composite rows ofbricks arranged alternately with said rows of silica bricks, each ofsaid composite rows consisting of basic bricks constituting a continuouspart of said row and silica bricks constituting the remainder of saidrow, the numbers of basic bricks being different in adjacent compositerows with the basic bricks at one end of said rows being positioned instaggered relation relative to each other, and ferrous metal coveringthe surfaces of the basic bricks which are exposed to gases in thefurnace.

3. In a metallurgical furnace having a chamber defined in part by anupstanding wall, a complete roof wall comprising a plurality of rows ofbricks extending from said wall upwardly and inwardly and partlydefining said chamber, certain of said f rows consisting of silicabricks, and certain other composite rows consisting of basic bricks andsilica bricks with the basic and silica bricks con-l stitutingrespectively the parts of said composite rows adjacent to and remotefrom said wall, theA basic brick portions of some of said composite rowsbeing shorter than the basic brick length of certain other rows ofbricks.

4. In a metallurgical furnace having a chamber defined in part by anupstanding side wall, a complete roof wall comprising a plurality of'transverse rows of bricks positioned to extend upwardly and at an angleto said side wall of the furnace, certain of said rows consisting ofsilica bricks and certain other rows arranged alter-I nately therewithand consisting of basic bricks positioned to extend upwardly from saidside walll and silica bricks to extendfrom the upwardmost basic bricks,the upwardmost basic bricks in adjacent composite rows being positionedto lie at different distances from said side wall and in4 upwardly andat an angle to said side wall of theV furnace, certain of said rowsconsisting of silica` bricks and certain other rows arranged altei-,nately therewith and consisting of basic bricks' positioned to extendupwardly from said side wall and silica bricks 1z0/extend from theupwardm'ost basic bricks, the upwardmostvbasicv bricks in adjacentcomposite rows being positioned to lie at different distances from saidside wall and in staggered relation relative to one another, and ferrousmetal covering the surfaces of the basic bricks which are exposed tofurnace gases.

6. In an open hearth furnace having a chamber defined in part byupstanding front and back walls, a complete roof wall comprising aplurality of transverse rows of bricks positioned to extend from theback wall of the furnace to its front wall at substantially right anglesto said walls, certain of said rows consisting'v of silica bricks andcertain other rows arranged alternately therewith and consisting ofbasic br'icks positioned to extend forwardly from the back wall andsilica bricks extending from the forwardmost basic bricks to the frontwall, the forwardmost basic bricks in adjacent composite rows lying atdifferent distances from the back wall and in different planes extending.longitudinally of the furnace.

7. In an open hearth furnace having a chamber defined in part byupstanding front and back walls, a complete roof wall comprising aplurality of transverse rows of bricks positioned to extend from theback wall of the furnace to its front Wall at substantially right anglesto said walls, certain of said rows consistingof silica bricks andcertain other rows arranged alternately therewith and consisting ofbasic bricks positioned'to extend forwardly from the back wall andsilica bricks extending from the forwardmost basic bricks to the frontwall, the forwardmost basic bricks in adjacent composite rows lying atdifferent distances from the back wall and in different planes extendinglongitudinally of the furnace, and ferrous metal covering the lowerexposed surfaces of said basic bricks.

8. In an electric furnaceV having a chamber defined in part by anupstanding generally circular outer wall, a completer roof wallcomprising a plurality of generally radial rows of bricks positioned toextend from the outer wall of the furnace to its center, certain of saidrows consisting of silica bricks and certain other rows arrangedalternately therewith and consisting of basic bricks positioned toextend from said periphery toward the center of the roof and silicabricks extending from the innermost basic bricks toward the center ofthe roof, the innermost basic bricks in adjacent rows containing basicbricks lying at different distances from the said periphery and indifferent circles concentric with said periphery.

9. In an electric furnace having a chamber defined in part by anupstanding generally circular outer wall. a complete roof wallcomprising a plurality of generally radial rows of bricks positioned toextend from the outer wall of the furnace to its center, certain of saidrows consisting of silica bricks and certain other rows arrangedalternately therewith and consisting of basic bricks positioned toextend from said periphery toward the center of the roof and silicabricks extending from the innermost basic bricks toward the center ofthe roof, the innermost basic bricks in adjacent rows containing basicbricks lying at different distances from the said periphery and indifferent circles concentric with said periphery, and ferrous metalcovering the lower exposed surfaces of the basic bricks.

CLARENCE G. POTH.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 1,672,524 Groninger June 5, 1928 1,686,386 Loftus Oct. 2, 19281,929,073 McDonald Oct. 3, 1933 2,068,863 j Mannshardt Jan. 26, 19372,085,837 Thomas July 6, 1937 2,216,813 Goldschmidt Oct. 8, 19402,236,920 Robertson Apr. 1, 1941 2,304,170 Heuer Dec. 8, 1942 FOREIGNPATENTS Number Country Date 807,010 France Oct. 5, 1936

